ISO 23945-2:2026

ISO 23945-2:2026 is an International Standard published by ISO for sampling fresh and hardened sprayed concrete. It specifies how to obtain samples of sprayed concrete or mortar in the laboratory or in situ, depending on the property being measured and the associated test method.

What does ISO 23945-2:2026 specify?

ISO 23945-2:2026 covers the method for taking samples of fresh or hardened sprayed concrete or mortar from either an in situ element or a test panel. The document is organized into clauses on scope, normative references, terms and definitions, principle, apparatus, procedures, and identification of sample, followed by a bibliography.

In practice, the standard is about getting a sample that matches the test purpose. That matters because sprayed concrete taken from the mixer, from the structure, or from a panel can behave differently after spraying and curing.

What are the key requirements of ISO 23945-2:2026?

ISO 23945-2:2026 focuses on controlling where the sample comes from, how it is taken, and how it is identified so that the test result can be linked back to the work.

• Clause 4, Principle - A fresh or hardened sample is extracted from an in situ element or from a test panel. For the reader, this means the sampling location has to match the property under test.

• Clause 5.1 to 5.2, Apparatus - The mixer shall conform to ISO 18650-1, and the spraying equipment shall spray stably and continuously. If an accelerator is used, the dosage device shall keep the accelerator content within the specified range. In practice, the equipment must not introduce variability into the sample.

• Clause 5.5 to 5.6, Moulds and cutting equipment - Moulds shall be rigid, non-water-absorbing, and large enough for the intended sampling method; the panel thickness and dimensions depend on hand spraying, robot spraying, and the test to be carried out. Coring or cutting equipment shall be suitable for the required sample dimensions. This matters because the panel has to survive spraying and still yield usable specimens.

• Clause 6.2 to 6.5, Fresh sampling and test panels - Fresh concrete may be taken from the basic mix before spraying, from in situ sprayed material before initial set, or from a test panel before initial set. The test panel is sprayed under conditions that match the actual work as closely as possible, including angle, distance, layer thickness, and equipment settings. This helps the sample represent the sprayed material rather than a different process condition.

• Clause 6.6 to 6.8, Curing and hardened sampling - Panels are protected against moisture loss, then cured at 20 °C ± 5 °C and at least 95 % relative humidity; hardened samples from panels are cored or sawn, and hardened in situ samples are obtained in accordance with ISO 1920-6. For testing, the curing history has to be controlled because it affects strength and other measured properties.

• Clause 6.9 and Clause 7, Size and identification - The shape and size of hardened samples shall meet the requirements of the relevant test method standard, and both fresh and hardened samples are marked with mix, location, specimen orientation, date, and operator. In practice, this gives traceability from the test result back to the sprayed concrete work.

Who uses ISO 23945-2:2026?

ISO 23945-2:2026 is used by people who sample sprayed concrete for quality control, testing, and assessment of sprayed work. The introduction points to use in tunnelling and mining ground support, as well as repairs, restoration, new construction, and other sprayed concrete applications.

Typical users include testing laboratories, site engineers, quality managers, and contractors who need repeatable sampling from fresh material, test panels, or hardened in situ concrete. The document is especially relevant when the test result depends on how and where the sample is taken.

Which standards are used with ISO 23945-2:2026?

ISO 23945-2:2026 cites two normative references:

• ISO 1920-6 - used for sampling, preparing, and testing concrete cores, and referenced for hardened samples taken from in situ sprayed concrete.
• ISO 18650-1 - used for concrete mixer requirements, which supports the sampling of the basic mix before spraying.

The foreword also says ISO 23945-2:2026 is intended for use with other parts of the ISO 23945 series, which provide requirements tied to the specified quality level and the execution method for sprayed concrete.

What does the ISO 23945-2:2026 document contain?

ISO 23945-2:2026 contains the procedure for fresh and hardened sampling, with separate routes for basic mix sampling, in situ sampling, test panels, and panel curing. It also includes the apparatus needed for sampling and for making panels, such as mixers, spraying equipment, scoops, trowels, moulds, and coring or cutting equipment.

The document includes Figure 1 for the spraying method and Figure 2 for the defective zone in a test panel. Those figures support practical work on panel preparation and on avoiding material that should not be used for test specimens.

It also sets out how to identify samples with waterproof marking and what information to record for traceability. That makes the document useful for laboratory preparation, site sampling, and reporting of sprayed concrete test specimens.